• Journal of the Korea Safety Management & Science
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• v.24 no.2
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• pp.143-154
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• 2022

Korea has the highest suicide rate in the world, and firefighters have the highest suicide rate among the professional population. As a result of the study, post-traumatic stress disorder education is essential in all occupations. Post-traumatic stress disorder is the most common disease and the biggest obstacle for firefighters in Korea. Firefighters who have suffered physical and mental damage in many types of disaster sites due to their extreme occupations are rapidly increasing the suicide rate in recent years. In order to maximize the effect of job training, education on post-traumatic stress disorder from new employees to leadership training is urgently needed.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.415-426
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• 2010

Post-grouting for the drilled shaft is known to increase the end bearing capacity of pile 2~3 times higher by consolidating and reinforcing the disturbed ground containing slime around the pile end. However, the general design guideline for post-grouting has not been established yet in Korea. Especially in the domestic application, the post-grouting is employed just for repairing the pile with the unacceptable resistance rather than for increasing the design resistance of pile. Therefore, little is reported about the effect of post-grouting on the pile resistance itself. In this study, the effect of post-grouting on the resistance of drilled shafts installed in the weathered rock in Korea was estimated by performing the bi-directional load tests on the piles with and without the post-grouting. The test results presented that the initial slope of end bearing-base displacement curve in the pile with post-grouting was 4 times higher than that without post-grouting. At the acceptable settlement (1% of pile diameter), the end bearing capacities of piles with and without the post-grouting were estimated to be 12.0 MPa and 7.0 MPa, respectively, indicating that the post-grouting could increase the end bearing resistance of pile in weathered rock more than 70%.

• Journal of Magnetics
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• v.15 no.4
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• pp.179-184
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• 2010

We have investigated the effects of post annealing on iron oxide nanoparticles synthesized by the novel hydrothermal synthesis method with the $FeSO_4{\cdot}7H_2O$. To investigate the post annealing effect, the as-synthesized iron oxide nanoparticles were annealed at different temperatures in a vacuum chamber. The morphological, structural and magnetic properties of the iron oxide nanoparticles were investigated with high resolution X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM), Mossbauer spectroscopy, and vibrating sample magnetometer analysis. According to the XRD and HRTEM analysis results, as-synthesized iron oxide nanoparticles were only magnetite ($Fe_3O_4$) phase with face-centered cubic structure but post annealed iron oxide nanoparticles at $700^{\circ}C$ were mainly magnetite phase with trivial maghemite ($\gamma-Fe_2O_3$) phase which was induced in the post annealing treatment. The crystallinity of the iron oxide nanoparticles is enhanced by the post annealing treatment. The particle size of the as-synthesized iron oxide nanoparticles was about 5 nm and the particle shape was almost spherical. But the particle size of the post annealed iron oxide nanoparticles at $700^{\circ}C$ was around 25 nm and the particle shape was spherical and irregular. The as-synthesized iron oxide nanoparticles showed superparamagnetic behavior, but post annealed iron oxide nanoparticles at $700^{\circ}C$ did not show superparamagnetic behavior due to the increase of particle size by post annealing treatment. The saturation of magnetization of the as-synthesized nanoparticles, post annealed nanoparticles at $500^{\circ}C$, and post annealed nanoparticles at $700^{\circ}C$ was found to be 3.7 emu/g, 6.1 emu/g, and 7.5 emu/g, respectively. The much smaller saturation magnetization value than one of bulk magnetite can be attributed to spin disorder and/or spin canting, spin pinning at the nanoparticle surface.

• The Journal of Korean Academic Society of Nursing Education
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• v.28 no.2
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• pp.193-203
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• 2022

Purpose: This study explored the mediating role of resilience between post-traumatic stress and emotional exhaustion in nurses during the COVID-19 pandemic. Methods: The data were collected from 193 nurses working at a hospital in Daegu from October 16 to 30, 2020, in the middle of the COVID-19 pandemic. Participants conducted self-reported surveys of post-traumatic stress (Impact of Event Scale-Revised Korean version), emotional exhaustion (Maslach Burnout Inventory), and resilience (Korean Resilience Quotient Test). The data were analyzed using descriptive statistics, frequency, t-tests, Mann-Whitney U tests, Kruskal-Wallis tests, Pearson correlation coefficients, and multiple regression. Mediation analysis was performed using the Baron and Kenny method and Sobel test. Results: The mean scores for post-traumatic stress, resilience, and emotional exhaustion were 16.18±16.18, 183.41±18.29, and 32.64±9.66, respectively. A higher level of post-traumatic stress was associated with lower resilience (r=-.20, p=.004) and with higher emotional exhaustion (r=.33, p<.001). A higher level of resilience was associated with lower emotional exhaustion (r=-.35, p<.001). The resilience was confirmed to have a partial mediating effect in the relationship between post-traumatic stress and emotional exhaustion, verified by the Sobel test (Z=2.31, p=.02). Conclusion: Resilience had a partial mediating effect in the relationship between post-traumatic stress and emotional exhaustion. Thus, nurses should develop individual strengths to reduce emotional exhaustion, and managers should also make efforts to increase the nurses' resilience. It is also necessary to develop and apply a program to strengthen nurses' resilience.

• Restorative Dentistry and Endodontics
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• v.12 no.2
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• pp.111-116
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• 1987

The experimental study was made to evaluate the influence of retentive grooves on the canal wall upon the retention of post, using different type of cements. Ninety periodontally involved anterior teeth were extracted and divided into six groups of 15 teeth. The groups were labeled as follows: Group I: Dentatus post cemented zincphosphate cement into post hole with smooth wall. Group II: Dentatus post cemented with zincphosphate cement into post hole with retentive grooves. Group III: Dentatus post cemented with glass-ionomer cement into post hole with smooth wall. Group IV: Dentatus post cemented with glass-ionomer cement into post hole with retentive grooves. Group V: Dentatus post cemented with composite resin adhesive into post hole with smooth wall. Group VI: Dentatus post cemented with composite resin adhesive into post hole with retentive grooves. The tensile strength was tested by an Instron type tester with cross-head speed of 5mm per minute. The results were as follows: In the group without retentive grooves, three kinds of cement have little effect upon retentive capacity of Dentatus post. The Dentatus post cemented on the canal wall with retentive grooves is more retentive than Dentatus post without retentive grooves.

• The Journal of Korean Physical Therapy
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• v.11 no.3
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• pp.97-106
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• 1999

The purpose of this study was to examine the effect of transcutaneous electrical nerve stimulation(TENS) in the patients of dysmenorrhea. A total of thirty subjects were assigned randomly to one of the two experimental groups or to a control group : 1) an Experimental group I received high-frequency TENS(100pps with a 100-microsecond pluse width), 2) an Experimental group II received low-frequency TENS(2pps with a 100-microsecond pulse width), 3) a Control group received medication(Acetaminophen 600mg). All subjects completed visual analogue scale(VAS) pre-treatment; after post-treatment; 1, 2, 3, 4, and 6 hours post-treatment; and the next morning. The results of study were as follows; 1. The mean pain scores decreased in thru groups. 2. The experimental group II and the control group exhibited a significant decrease in pain post - treatment. 3. The experimental group I had the pain relief obtained after three hours post - treatment. The experimental group II had the pain relief obtained immediately after the post - treatment Control group had the pain relief obtained immediately after the post - treatment, but increased pain after four hours of post-treatment. Finally. this result suggests that TENS can reduce significantly the pain of dysmenorrhea. Besides. low-frequency TENS provided a good result to the excellent subjective pain relief in the subject, compared with high-frequency TENS and medication.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1034-1039
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• 2004

The major objective of this study is to investigate the effects and application of reinforcement for steel plate girder railway bridge by the external prestressing method. It analyzed the mechanical behaviors of non-ballasted railway bridge with ballast reinforced and external post-tensioning reinforced on the finite clement analysis for the static and dynamic behavior. As a result, the reinforcement of ballasted railway bridge the external prestressing method are obviously effective for the additional dead force which is ballast. The analytical study are carried out to investigate the post-tension force decrease bending behavior and deflection in composite bridge for serviceability. To develop two type FEM model which reflect well the post-tension force transverse distribution behavior of servicing bridge. With the comparing the results of railway bridge with ballast which carried out before the post-tensioning with the results of railway bridge with ballast which carried out after post-tensioning, It is investigated that the additional dead load decrease effect and bending behavior of servicing bridge is effect by the post-tensioning. The reinforcement by using the external tendon can be reducing that structure of a degradation phenomenon by unusual stresses due to additional dead load and other problems.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.7
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• pp.775-786
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• 2011

This study examines whether there are differences in the evaluation of clothing products according to self-efficacy in purchasing clothes. A total of 300 surveys were distributed and 231 were used for analysis. The data were analyzed by regression and factor analysis. The results are as follows. First, there were significant differences in the product attributes considered according to self-efficacy in purchasing clothes. The consumers with high self-efficacy considered diverse product attributes comprehensively when making purchase decisions and had significantly higher score in perceived value and post-purchase satisfaction level than the consumers with low self-efficacy. Second, there were differences in the attributes of clothing products that effects perceived value according to self-efficacy in purchasing clothes. The attributes of 'clothes that I like' and 'necessary clothes' had a significant effect on perceived value for both consumers. The attributes of 'design that suits me' and 'inexpensive price' had significant effect on perceived value on consumers with high self-efficacy while the attributes of 'harmony with other clothes' had a significant effect on perceived value for consumers with low self-efficacy. Third, there were differences in product attributes and the perceived value that influenced post-purchase satisfaction level according to self-efficacy in purchasing clothes. The attributes of 'design that suits me' and perceived value had a direct effect on the post-purchase satisfaction level four consumers with a high self-efficacy. For the consumers with low self- efficacy, the attributes of 'clothes I like', 'necessary clothes', and 'design similar to that of usually purchased products' had a direct effect on post-purchase satisfaction level; however, the effect of perceived value was not found.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.179-182
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• 2012

Effect of double post injections on diesel PCCI combustion with focus on HC emission was investigated in a single-cylinder direct-injection diesel engine. The ISFC, HC and CO emissions were reduced by single or double post injections. The application of double post injections could also improve the trade-off relationship between NOx and HC emissions under wide EGR rate range.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.4
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• pp.343-346
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• 1990

A study was conducted to determine the effect of prostaglandin $F_2$ alpha ($PGF_2$ alpha) on the reaction time and seminal characteristics of buffalo bulls. Semen was collected from three Murrah bulls in three periods: pre-treatment, treatment and post-treatment. During the treatment period each bull was administered 2 ml $PGF_2$ alpha (Synchrocept, Fenprostalene) im, 1 hour prior to semen collection. In the post-treatment, semen was collected 7 days after the last injection of $PGF_2$. Semen samples were evaluated immediately after collection. Pre-collection injection of $PGF_2$ alpha has no significant effect on reaction time, semen volume, percentage motility, sperm concentration and total number of sperms per ejaculate. Fluctuations in semen color and consistency were observed. There is a significant (p<0.05) increase in the mean percentage of normal spermatozoa during the treatment and post treatment periods. Likewise, administration of PG results into a significant (p<0.05) rise on the average percentage of live sperms but this effect was not manifested in the post-treatment period. Improvement in mass activity was observed during the treatment and post-treatment periods.